This document describes the first version of the graphical server protocol. An implementation of the complete protocol described here can be found in the web-based prototype of Eclipse Sirius realized by Obeo. This prototype has been created on top of Sprotty which has defined and implemented the core parts of this protocol.
The following TypeScript definitions describe the base protocol:
A general message as defined by JSON. It holds the action that are transmited between the client and the server.
class ActionMessage {
/**
* Used to identify a specific client.
*/
public readonly clientId: string;
/**
* The action to execute.
*/
public readonly action: Action;
}Action messages processed by the client or the server do not automatically require a response. Additional information regarding the lifecycle of some action messages can be found in the Sprotty documentation.
Actions contained in the action messages are identified by their kind attribute. This attribute is required for all actions. Some actions may most of the time be supported only by a client or only by the server but they can be supported by both clients and servers in theory depending on the situation. All actions must extend the default action interface.
interface Action {
/**
* Unique identifier specifying the kind of action to process.
*/
readonly kind: string;
}Centers the viewport on the elements with the given identifiers. It changes the scroll setting of the viewport accordingly and resets the zoom to its default. This action can also be created on the client but it can also be sent by the server in order to perform such a viewport change remotely.
class CenterAction implements Action {
/**
* The kind of the action.
*/
public readonly kind = 'center';
/**
* The identifier of the elements on which the viewport should be centered.
*/
public readonly elementIds: string[];
/**
* Indicate if the modification of the viewport should be realized with or without support of animations.
*/
public readonly animate: boolean = true;
}Recalculates a diagram when some specific elements are collapsed or expanded. This action can be sent by a client to the server to let the server compute a new version of the diagram.
class CollapseExpandAction implements Action {
/**
* The kind of the action.
*/
public readonly kind = 'collapseExpand';
/**
* The identifier of the elements to expand.
*/
public readonly expandIds: string[];
/**
* The identifier of the elements to collapse.
*/
public readonly collapseIds: string[];
}Collapses or expands all the elements of the diagram.
export class CollapseExpandAllAction {
/**
* The kind of the action.
*/
public readonly kind = 'collapseExpandAll';
/**
* Indicates if the elements should be expanded (true) or collapsed (false)
*/
public readonly expand: boolean = true;
}Sent from the client to the model source (e.g. a DiagramServer) to transmit the result of bounds computation as a response to a RequestBoundsAction. If the server is responsible for parts of the layout (see needsServerLayout viewer option), it can do so after applying the computed bounds received with this action. Otherwise there is no need to send the computed bounds to the server, so they can be processed locally by the client.
export class ComputedBoundsAction implements Action {
/**
* The kind of the action.
*/
public readonly kind = 'computedBounds';
/**
* The new bounds of the diagram elements.
*/
public readonly bounds: ElementAndBounds[];
/**
* The revision number.
*/
public readonly revision?: number;
/**
* The new alignment of the diagram elements.
*/
public readonly alignments?: ElementAndAlignment[];
}The ElementAndBounds type is used to associate new bounds with a model element, which is referenced via its id.
class ElementAndBounds {
/**
* The identifier of the element.
*/
public readonly elementId: string;
/**
* The new bounds of the element.
*/
public readonly newBounds: Bounds;
}The bounds are the position (x, y) and dimension (width, height) of an object. As such the Bounds type extends both Point and Dimension.
class Bounds extends Point, Dimension {
}A Point is composed of the (x,y) coordinates of an object.
class Point {
/**
* The abscissa of the point.
*/
public readonly x: number;
/**
* The ordinate of the point.
*/
public readonly y: number;
}The Dimension of an object is composed of its width and height.
class Dimension {
/**
* The width of an element.
*/
public readonly width: number;
/**
* the height of an element.
*/
public readonly height: number;
}The ElementAndAlignment type is used to associate a new alignment with a model element, which is referenced via its id.
class ElementAndAlignment {
/**
* The identifier of an element.
*/
public readonly elementId: string;
/**
* The new alignment of the element.
*/
public readonly newAlignment: Point;
}Triggered when the user requests the execution of a container creation tool.
class ExecuteContainerCreationToolAction implements Action {
/**
* The kind of the action.
*/
public readonly kind = 'executeContainerCreationTool';
/**
* The name of the container creation tool to execute.
*/
public readonly toolName: string;
}Triggered when the user requests the execution of a node creation tool.
class ExecuteNodeCreationToolAction implements Action {
/**
* The kind of the action.
*/
public readonly kind = 'executeNodeCreationTool';
/**
* The name of the node creation tool to execute.
*/
public readonly toolName: string;
}Triggered when the user requests the execution of a generic tool.
class ExecuteToolAction implements Action {
/**
* The kind of the action.
*/
public readonly kind = 'executeTool';
/**
* The name of the generic tool to execute.
*/
public readonly toolName: string;
}Used to export the diagram as an SVG image.
class ExportSvgAction implements Action {
/**
* The kind of the action.
*/
public readonly kind = 'exportSvg';
/**
* The SVG image data.
*/
public readonly svg: string;
}Triggered when the user requests the viewer to fit its content to the available drawing area. The resulting FitToScreenCommand changes the zoom and scroll settings of the viewport so the model can be shown completely. This action can also be sent from the model source to the client in order to perform such a viewport change programmatically.
class FitToScreenAction implements Action {
/**
* The kind of the action.
*/
public readonly kind = 'fit';
/**
* The identifier of the elements to fit on screen.
*/
public readonly elementIds: string[];
/**
* The padding that should be visible on the viewport.
*/
public readonly padding?: number;
/**
* The max zoom level authorized.
*/
public readonly maxZoom?: number;
/**
* Indicate if the action should be performed with animation support or not.
*/
public readonly animate: boolean = true;
}Used to indicate that an element has been opened. The default behavior will be triggered when an end user double click on an element. It can allow a diagram server to react to this event.
class OpenAction implements Action {
/**
* The kind of the action.
*/
public readonly kind = 'open';
/**
* The identifier of the element.
*/
public readonly elementId: string;
}Sent from the model source to the client to request bounds for the given model. The model is rendered invisibly so the bounds can derived from the DOM. The response is a ComputedBoundsAction. This hidden rendering round-trip is necessary if the client is responsible for parts of the layout.
class RequestBoundsAction implements Action {
/**
* The kind of the action.
*/
public readonly kind = 'requestBounds';
/**
* The diagram elements to consider to compute the new bounds.
*/
public readonly newRoot: SModelRootSchema;
}Used to request the export of the diagram as an SVG image.
class RequestExportSvgAction implements Action {
/**
* The kind of the action.
*/
public readonly kind = 'requestExportSvg';
}Sent from the client to the server in order to request diagram layers. With RequestModelAction and RequestToolsAction, they are the firsts messages that are sent to the server. The response is a SetLayersAction.
class RequestLayersAction implements Action {
/**
* The kind of the action.
*/
public readonly kind = 'requestLayers';
}Sent from the client to the model source (e.g. a DiagramServer) in order to request a model. Usually this is the first message that is sent to the source, so it is also used to initiate the communication. The response is a SetModelAction or an UpdateModelAction.
class RequestModelAction implements Action {
/**
* The kind of the action.
*/
public readonly kind = 'requestModel';
/**
* Additional options used to compute the diagram.
*/
public readonly options?: { [key: string]: string });
}Triggered when the user hovers the mouse pointer over an element to get a popup with details on that element. This action is sent from the client to the model source, e.g. a DiagramServer. The response is a SetPopupModelAction.
class RequestPopupModelAction implements Action {
/**
* The kind of the action.
*/
public readonly kind = 'requestPopupModel';
/**
* The identifier of the element for which a popup is requested.
*/
public readonly elementId: string;
/**
* The bounds.
*/
public readonly bounds: Bounds;
}Sent from the client to the server in order to request diagram tools. With RequestModelAction and RequestLayersAction, they are the firsts messages that is sent to the server. The response is a SetToolsAction.
class RequestToolsAction implements Action {
/**
* The kind of the action.
*/
public readonly kind = 'requestTools';
}Triggered when the user changes the selection, e.g. by clicking on a selectable element. The action should trigger a change in the selected state accordingly, so the elements can be rendered differently. This action is also forwarded to the diagram server, if present, so it may react on the selection change. Furthermore, the server can send such an action to the client in order to change the selection remotely.
class SelectAction implements Action {
/**
* The kind of the action.
*/
public readonly kind = 'elementSelected';
/**
* The identifier of the elements to mark as selected.
*/
public readonly selectedElementsIDs: string[] = [];
/**
* The identifier of the elements to mark as not selected.
*/
public readonly deselectedElementsIDs: string[] = [];
}Used for selecting or deselecting all elements.
class SelectAllAction implements Action {
/**
* The kind of the action.
*/
public readonly kind = 'allSelected';
/**
* If `select` is true, all elements are selected, othewise they are deselected.
*/
public readonly select: boolean = true;
}Sent by the external server when to signal a state change.
class ServerStatusAction implements Action {
/**
* The kind of the action.
*/
public readonly kind = 'serverStatus';
/**
* The severity of the status.
*/
public readonly severity: string;
/**
* The message describing the status.
*/
public readonly message: string;
}Sent from the model source (e.g. a DiagramServer) to the client to update the bounds of some (or all) model elements.
class SetBoundsAction implements Action {
/**
* The kind of the action.
*/
public readonly kind = 'setBounds';
/**
* The elements to update with their new bounds.
*/
public readonly bounds: ElementAndBounds[];
}Sent from the server to the client in order to set the diagram layers. If layers are already presents, they are replaced.
class SetLayersAction implements Action {
/**
* The kind of the action.
*/
public readonly kind = 'setLayers';
/**
* The layers of the diagram.
*/
public readonly layers: Layer[];
}interface Layer {
/**
* The identifier.
*/
readonly id: string;
/**
* The name.
*/
readonly name: string;
/**
* Indicates if the layer is currently active or not.
*/
readonly isActive: boolean;
}Sent from the model source to the client in order to set the model. If a model is already present, it is replaced.
class SetModelAction implements Action {
/**
* The kind of the action.
*/
public readonly kind = 'setModel';
/**
* The new diagram elements.
*/
public readonly newRoot: SModelRootSchema;
}Sent from the model source to the client to display a popup in response to a RequestPopupModelAction. This action can also be used to remove any existing popup by choosing EMPTY_ROOT as root element.
class SetPopupModelAction implements Action {
/**
* The kind of the action.
*/
public readonly kind = 'setPopupModel';
/**
* The model elements composing the popup to display.
*/
public readonly newRoot: SModelRootSchema;
}Sent from the server to the client in order to set the available tools. A tool is available only if the layer that contains the tool is activated. If tools are already presents, they are replaced.
class SetToolsAction implements Action {
/**
* The kind of the action.
*/
public readonly kind = 'setTools';
/**
* The Tools of the diagram.
*/
public readonly tools: Tool[];
}
interface Tool {
/**
* The tool identifier.
*/
readonly id: string;
/**
* The tool name.
*/
readonly name: string;
/**
* The tool type.
*/
readonly toolType: string;
}Sent from the client to the server in order to toggle a layer. The model, the layers and the tools may be updated after the changes.
class ToggleLayerAction implements Action {
/**
* The kind of the action.
*/
public readonly kind: string = 'toggleLayer';
/**
* The name of the layer.
*/
public readonly layerName: string;
/**
* The new state of the layer.
*/
public readonly newState: boolean;
}Sent from the model source to the client in order to update the model. If no model is present yet, this behaves the same as a SetModelAction. The transition from the old model to the new one can be animated.
class UpdateModelAction implements Action {
/**
* The kind of the action.
*/
public readonly kind = 'updateModel';
/**
* The new root element of the diagram.
*/
public readonly newRoot?: SModelRootSchema;
/**
* The matches used while comparing the diagram elements.
*/
public readonly matches?: Match[];
/**
* Indicates if the update should be performed with animation support or not.
*/
public readonly animate: boolean = true;
}